1. Field of the Invention
The present invention relates to a positioning drum, and more particularly to a slat-positioning drum for a Venetian blind.
2. Description of Related Art
With reference FIG. 7, a first conventional slat-positioning drum (60) for a venetian blind (not shown) in accordance with the prior art is rotatably mounted in a retaining base (not shown) which is fixedly mounted in a head rail (not shown) of the venetian blind. The slat-positioning drum (60) has a top, a front side, a rear side, two ends and a central axis parallel to the top and sides. A rotary shaft (not shown) extends through an axial bore (62) longitudinally defined along the central axis of the drum (60) to control rotational movement of the drum (60). A pair of retaining clips (61) are formed on the top of the slat-positioning drum (60). Each retaining clip (61) has a proximal end (612) fixedly formed on the top of the slat-positioning drum (60) and a free distal end slightly separated from the top of the slat-positioning drum (60). A slit (611) is defined between each of the retaining clips (61) and the top of the slat-positioning drum (60). A pair of slat cords (41) is clipped under the retaining clips (61). Each slat cord (41) has a first free end that extends through a corresponding one of the slits (611). A rigid tag is attached to the free end of each of the cords (41) and is securely retained by the fixed distal end (612) of the associated retaining clip (61). Each of the two cords (41) has a second free and extending downwardly to fasten one side of a plurality of slats (not shown) so as to control the angular position of the plurality of slats.
With such an arrangement, the retaining clip (61) is easily detached from the fixed distal end (612) of the retaining clip (61) such that the free end of the cord (41) is easily released from the slit (611).
With reference to FIG. 8, a second conventional slat-positioning drum (50) for a venetian blind (not shown) in accordance with the prior art is rotatably mounted in a retaining base (not shown) which is fixedly mounted in a head rail (not shown) of the venetian blind. The slat positioning drum (50) has a flat top surface (51), a front side, a rear side, two ends and a central axis parallel to the top and sides. A rotary shaft (not shown) extends through an axial bore (56) longitudinally defined along the central axis of the drum (50) to control rotational movement of the drum (50). Two mounting clips, each consisting of a long tongue (52) and short tongue (53), are formed on the top surface (51) of the drum (50) with a space (58) between the tongues (52, 53). One pair is formed near the front side of the drum (50), and the other is formed near the rear side of the drum (50). A slit (54) is defined between each tongue (52, 53) and the flat top surface (51). A pair of flexible slat tapes (40) is selectively attached to the drum (50). Each flexible slat tape (40) has a loop (not numbered) formed on a first free end such that a corresponding pair of long and short tongues (52, 53) are inserted into the loop to hold the free end of each of the tape (40) in place. Each of the two tapes (40) has a second free end extending downward to hold a plurality of slats (not shown) and control angular position of the slats.
Because the space (58) between the long and short tongues (52, 53) is short, it is not easy insert the loop of the first free end of the tapes (40) on the tongues (52, 53). If the space (58) between the tongues (52, 53) is large enough to easily connect the loops to the tongues (52, 53), the loop is easily released from the tongues (52, 53).
The present invention has arisen to mitigate and/or obviate the disadvantages of conventional slat-positioning drums for Venetian blinds.
The main objective of the present invention is to provide an improved slat-positioning drum that has a rigid engaging structure and makes the associated assembly of the venetian blind easier. To achieve the objective, the slat-positioning drum in accordance with present invention comprises a body having a hollow upper section, two ends, a front side, a rear side and a top plate. Two parallel channels are longitudinally defined in the upper section of the body, and each channel has a closed end and an open end. The closed ends of the two channels are opposite to each other. Two parallel grooves are each longitudinally defined in the top plate and respectively communicate with one of the two corresponding channels. Multiple teeth are formed on each of two sides defining each of the two grooves. An elongated rod is formed in each of the two channels and is located below an associated groove. The elongated rods extend from the corresponding closed ends of the channels.
Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings.